The specific aims of this study are to establish the potential efficacy and side effect profiles of methotrexate 50 mg orally for the medical treatment of extrauterine pregnancy. This trial is based on the hypothesis that methotrexate 50 mg orally will be 90% effective (approximately equal to methotrexate 50 mg/m2 intramuscularly) for the medical treatment of ectopic pregnancy. Since the oral regimen has never been evaluated as primary treatment, it is necessary to perform a pilot study as an initial investigation of its safety and efficacy.